Core drill



March 27, 1934. G HARRlNGTQN I 1,952,165

CORE DRILL Filed Sept. 23. 1952 INVENTOR.

WAC ATTORNEY.

Patented Mar. 27, 1934 CORE DRILL George G. Harrington, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application September 23, 1932, Serial No. 634,470

2 Claims. (Cl. Z55-72) UNITED STATES PATENT OFFICE This invention relates to core drills particularly adapted for drilling deep wells.

In deep well drilling it is customary to pump muddy water, or slush, down through the drill l stem to keep the cutters of the bit cool and to remove the cuttings thereof. The conventional core drill includes a drill stem, to the lower end of which is secured a bit having a central .opening, and a core barrel within the stem to receive and retain the core entering said opening. In the upper portion of the core barrel is a valve to permit the escape of fluid that would otherwise be confined in the corebarrel as the core moves upwardly therein and to prevent the entrance of slush into the barre1 so that^the core will not be washed away. It is desirable to wash out the core barrel by pumping the slush through the core barrel after the drill is in the well, and before drilling operations begin, and this can- 90 not be done with the conventional core barrel because the valve keeps the slush out of the core barrel.

This invention has for its general object the provisions of new and improved means whereby the valve is held open so that slush may be pumped through the core barrel, and then automatically closed for the drilling operations.

More specifically, the invention provides new and improved means whereby the driller need only lower the drill into the well, pump slush down through the drill stern and core barrel to wash the latter, vary the pressure of the slush, whereupon the valve will automatically close so that slush cannot enter the core barrel during drilling operations, and then proceed with drilling in the usual manner.

The preferred embodiment of. the invention is illustrated by the accompanying drawing, wherein Fig 1. is a`partly sectional elevation of the drill;

l 4 Fig. 2 an enlarged fragmentary sectional elevation showing the valve before slush is pumped through the drill stem; Fig. 3 a detail view illustrating the valve while the slush is being pumped through the drill stem and core barrel; and Fig. 4 a detail view illustrating how the valve is released when the pressure of the slush is reduced.

In the drawing the drill stem is indicated at 1. It has secured to its lower end a bit 2, having a central opening 3. Within the drill stem 59 1 and adapted to receive the core entering through the opening 3 is a core barrel 4. The core barrel 4 is substantially concentric with and spaced from the drill stem 1 so that slush may be pumped downwardly between the drill stem 1 and core barrel 4 to pass out of the uid passageways 5 to keep the bit 2 cool and remove the cuttings there- The upper portion of the core barrel 4 is in communication with the interior of the drill V stem 1. When the valve 8 is Vnot on the seat 00 7 slush may pass into the core barrel 4 through the openings 6. When the valve 8 is on the seat 7 slush cannot pass from the interior of the drill stem 1 into the core barrel 4, but uid may escape from the core barrel 4 outwardly 55 through the openings 6.

The valve 8 is normally held in a socket 4a away from the seat 7 by the rst dog 9, which is pivotally mounted on the core barrel 4 and yieldably held in its active position by the spring 10.

Below the rst dog 9 is a second dog 11 also pivotally mounted on the core barrel.

On the upper end of the core barrel is movably mounted a dog actuating cap 12, held thereon by the pin 13, fitting in elongated slot 14, and 76. urged upwardly by the spring 14 which bears against the upper end of the core barrel and the inner end wall of the cap. Openings 15 may be provided in the cap 12 so that fluid in the drill stem may move into and-out of the'cap as the 80 cap moves up and down so that the free movement of the cap will not be interfered with.

The drill is used as follows:

The ball valve 8 having been placed in the socket 4a of the core barrel 4 above the dogY 9, 85 and the parts being in the position shown by Fig.

2, the drill is lowered into the well. In order to wash out the core barrel 4, the driller then pumps slush down through the drill stem. This slush passes into the core barrel 4 through the open- 90 ing 6 and seat 7. 'The pressure of the slush is suflicient to move the cap 12 downwardly against the resistance of the spring 14 from the position shown by Fig. 2 into the position shown by Fig.

3. The first dog 9 is thereby rotated on its pivot 95 into its inactive position, the resistance of the spring 10 being overcome. The ball 8, being released by the rst dog 9, thereupon falls downwardly. But meanwhile the cap 12 has rotated the second dog 11 into its active position and is 100 holding it in that position, so the ball 8 is caught by the second dog 11 and is held as shown by Fig. 3. Now after the core barrel 4 has been washed out by the slush, the driller reduces the pressure of the slush suiciently to enable the spring 14 to return the cap 12 to its inactive position. The second dog 11 is thereby released so that it may be swung out of .the way by the ball 8, whereupon the ball 8 will fall upon the seat 7 to close the core barrel. 11

The driller may then rotate the drill to penetrate the formation and proceed with drilling in the usual manner, the ball 8 being then upon the seat 7 and serving to permit the escape from the core barrel of fluid that would otherwise be conned therein and to prevent the entrance into the core barrel of the slush pumped through the drill stem.

The invention is not limited to the preferred embodiment herein disclosed. Various changes may be made within the scope of the following claims.

I claim:

1. A core drill having a stem; a bit to which fluid may be pumped through said stem; a core barrel within said stem and having adjacent its upper end an opening communicating with the interior of said stem; a valve for said opening; first and second valve holding vdogs movably mounted on said barrel; a dog actuating cap movable on the upper end of said barrel; a spring to yieldably hold said cap in its upper inactive position; said rst dog being normally in its active position to hold said Valve away from said opening; said cap being movable by fluid under pressure in said stem to move said rst dog into its inactive position to release said valve, and to hold said second dog in its active position to catch said valve before it closes said opening, so that said fluid under pressure may pass through said core barrel; said spring serving to return said cap to its inactive position when said fluid pressure is reduced to permit said second dog to release said valve so that said valve may close said opening.

2. A core drill having a stem; a bit to which iiuid may be pumped through said stem; a core barrel within said stem and having an opening communicating with the interior of said stem; a valve arranged to close said opening to prevent the entrance of iiuid from the interior of said stern into said barrel; and means to hold said valve to prevent closure of said opening so that fluid may be pumped through said barrel; said means being constructed to release said valve to permit closure of said opening when the fluid in said stem is given a predetermined pressure and said pressure is reduced a predetermined amount.

GEORGE G. HARRINGTON. 

